Bituminous compositions containing amorphous polypropylene and an ethylene-vinyl acetate copolymer



United States Patent i 3,309 329 BITUMINOUS COMPOSITIONS CONTAININGAMORPHOUS POLYPRQPYLENE AND AN ETHYLENE-VINYL ACETATE COPOLYMER3,309,329 Patented Mar. 14, 1967 "ice When using these novel additives,therefore, there is neither a risk that the sheet absorbs the plastifiernor that the bituminous mass becomes brittle by the disintegration orexudation of the plastifier. The system always main- Gerhart Schultz,Frankfurt am Main, and Guido Max films the desired P y- Rudolf Lorentz,Oes, near Butzbach, Germany, as- Another advantage is that the additivesare well comsignors to Farbwerke Hoechst Aktiengesellschaft vorpatiblewith bitumen. They are easy to incorporate and mals M s er u s & g,Frankfurt am Main remain homogeneous. This is especially important wheny, a 'pP of Germany the masses are admixed with fillers, such as stonepowder No P P F'led 1962 241,560 or stone splinters of all kind. Suchmasses containing Claims priority,app lcatgg gi 1961 fillers are oftenfabricated in the heat. In this case it is especially important thatdisintegration does not take 6 Claims (CL 260-285) place. It was foundto be very advantageous that the It has been known to use high polymerichydrocarbons, masses according to the invention always maintain theirexample p y y as additives r bituminOuS homogeneity even on repeatedheating in the fusion ketmasses. It has also been known to usecaoutchouc as tle. It is ofspecial advantage that the additivesacadditive for bitumen and asphalt, in which connection cording to theinvention can withstand temperatures of there is understood bycaoutchouc both synthetic up to 250 C. so that they are permanentlycapable of caoutchouc and natural caoutchouc. Both types ofadwithstanding the melting process. ditives entail disadvantages.Polyethylenes are compat- This constitutes an important advantage overthe adible with bitumen to a limited extent only. Although the ditivesresembling caoutchouc which, as is well-known, polyethylenes increasethe dropping point, they diminish are not capable of permanentlywithstanding the high the breaking point (according to Fraas). Moreover,an melting temperatures normally applied in the case of addition ofpolyethylene deteriorates the resistance to bitumen. In comparison withthe other known additives, aging of the bituminous mixtures. Afterexposure to the additives according to the invention are not onlyultra-violet irradiation, the masses tend to become britcapable ofinfluencing the plasticity range in a higher tle in an increased degree.When using caoutchouc large degree but they also possess an increasedstability against amounts of additives are required in order to attaingood ultra-violet irradiation which is shown in the following effects.Table 1 in which:

Now we have found that bituminous binding agents VA is an amorphousethylene/vinyl acetate co such as bitumen, tars and asphalts can readilybe plastified polymer with a vinyl acetate content of 38 percent by bythe addition thereto of small amounts of a mixture weight, aflowing/dropping point of 71.5/86.5 C., a melt of amorphous, polymerichydrocarbons, especially therviscosity of 43,500 centistokes at 120 C.,a density of mally degraded polypropylenes and predominantly amor- 0.953at 20 C., which was obtained by copolymerizing phous copolymers ofunsaturated hydrocarbons with 35 the two components under elevatedpressure in the presunsaturated organic compounds containing at leastone ence of free radical-forming compounds (for example oxygen atom permolecule, especially copolymers of according to the process of GermanPatent 912,267). ethylene and vinyl acetate, preferably those having aThe product does not contain crystalline portions (penevinyl acetatecontent of 25 to percent by weight. trometer number: 66; measuredaccording to German In- The range of plasticity of the bituminousbinding agents dustrial Standards 51,579). is considerably enlarged bythe additives, i.e. both the CP signifies cracked polypropylene obtainedby thermal dropping point and the softening point are increased.degradation of amohphous polypropylene, according to The breaking point(according to Fraas), however, is dethe process of Belgian Patent616,420, which after crackcreased. The addition of the aforementionedhigh moing has a flowing/dropping point of 154/ 155 C. and a lecularsubstances in small quantities, i.e. in amounts 45 viscosity of 120centipoises at 180 C. The process of ranging from 1 to 10 percent byweight, preferably 2 the Belgian patent involves heating a viscous tosemito 4 percent by weight, in each case, calculated on the solidpolypropylene polymer having a substantially rubbituminous binding agentfor each component, brings her-like character and a density within therange of 0.82 about the plastification of the bitumen without incorpoto0.89, a melt viscosity at 120 C. within the range of rating therein aso-called migrating substance. There is 59 10,000 to 1,000,000centistokes and an average molecular no fear, therefore, of adisintegration or exudation of the weight within the range of 3,000 to20,000 at a temperasubstances added. This property is especiallyimportant ture within the range of from 280 to 400 C. for a period whenbringing together bitumen with sheets of plastic maof from 1 to 150minutes to obtain an amorphous polyterials which are sensitive toplastifiers, e.g. sheets of unpropylene with the desired properties such'as viscosity plastified polyvinyl chloride or sheets ofpolyisobutylene. and density.

TABLE 1 Indentation depth 4 after se- Droppmg Softening Breaking ends inmm. at Type of bitumen Additive point, C. point, C. point, C.

Bitumen 45 (German Industrial \Ione 78/78 526/526 7 72.2 25.7 Standards1995). 40.. 110/112 610/672 liogs/glisgtumen (Blown Bitumen None /10078/78 1 According to Ubhclhode (German Industrial Standards 1995 U3).

According to ring and ball (German Industrial St 3 According GermanIndustrial Standards 1995 U7.

The resistance to aging of these mixtures is shown below.

TABLE 2 Measure- Measurements after 18 days 5 Hot bitumen merits storageat C in a condi- (blown bitumen shortly tioning cabinet with exposure 2after to intense ultra-violet mixing irradiation C.)

Dropping point: 10

W ithont additive According to footnote 1,

Table 1 136 Softening point:

Without additive 78 80 According to iootnote 2,

Tablel 85 as 15 Breaking point (according to Frans):

Without additive 10 8. 5 According to footnote 3,

Table 1 15 -14. 5

20 Table 2 shows that the bitumen containing no additive has undergone aconsiderable change already after a 450 hours storage at 50 C. withultra-violet irradiation.

We claim: 1. Composition of matter consisting essentially of 21 Q5bituminous binding agent, 1-10 percent by weight, calculated on thebituminous binding agent, of an amorphous cracked polypropylene having aviscosity in the melt after cracking of 120 centipoises at C. and l-10percent by weight, calculated on the bituminous binding agent, of anamorphous copolymer of ethylene and vinyl acetate having a vinyl acetatecontent of 25-50 percent by weight,

calculated on the copolymer.

2. Composition of matter consisting essentially of a bituminous bindingagent, 2-4 percent by weight, calculated on the bituminous bindingagent, of an amorphous cracked polypropylene having a viscosity in themelt after cracking of 120 centipoises at 180 C. and 2-4 percent byWeight, calculated on the bituminous binding agent, of an amorphouscopolymer of ethylene and vinyl acetate having a vinyl acetate contentof 30-40 percent by weight, calculated on the copolyrner.

3. A composition according to claim 1 wherein said bituminous bindingagent is a member selected from the group consisting of bitumen, tar andasphalt.

4. A composition according to claim 3 wherein said bituminous bindingagent is bitumen.

5. A composition according to claim 3 wherein said bituminous bindingagent is tar.

6. A composition according to claim 3 wherein said bituminous bindingagent is asphalt.

References Cited by the Examiner FOREIGN PATENTS 11/1946 Great Britain.

30 MORRIS LIEBMAN, Primary Examiner.

D. C. KOLASCH, I. A. GAZEWOOD, B. A. AMER- NICK, Assistant Examiners.

1. COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF A BITUMINOUS BINDINGAGENT, 1-10 PERCENT BY WEIGHT, CALCULATED ON THE BITUMINOUS BINDINGAGENT, OF AN AMORPHOUS CRACKED POLYPROPYLENE HAVING A VISCOSITY IN THEMELT AFTER CRACKING OF 120 CENTIPOISES AT 180*C. AND 1-10 PERCENT BYWEIGHT, CALCULATED ON THE BITUMINOUS BINDING AGENT, OF AN AMORPHOUSCOPOLYMER OF ETHYLENE AND VINYL ACETATE HAVING A VINYL ACETATE CONTENTOF 25-50 PERCENT BY WEIGHT, CALCULATED N TH COPOLYMER.